The present invention relates to apparatus for accumulating arrays of parallel rod-shaped articles, such as plain or filter tipped cigars, cigarillos, cigarettes or cheroots. More particularly, the invention relates to improvements in apparatus for accumulating multi-layer arrays of parallel rod-shaped articles (hereinafter referred to as cigarettes), preferably for accumulating arrays wherein the cigarettes forming the neighboring layers are slightly offset relative to one another so that the cigarettes of one layer extend into the recesses of the adjacent layer or layers. Still more particularly, the invention relates to improvements in apparatus which are designed for stepwise accumulation of multi-layer arrays of cigarettes.
It is already known to accumulate multi-layer arrays of cigarettes in an apparatus which forms part of a cigarette packing machine and wherein a magazine has several sections or units, one for each layer of an array, and wherein each such section or unit is designed to accumulate a succession of layers consisting of closely adjacent parallel cigarettes. A conveyor which supports a series of equidistant receptacles for discrete arrays is caused to advance stepwise past the sections of the magazine so that successive receptacles register with successive sections during successive intervals of dwell of the conveyor. The sections have outlets which are disposed at different levels so that the layer which issues from a next-following section of the magazine can descend onto the layer which was introduced into the same receptacle during dwell of such receptacle in a position of register with the preceding section or unit of the magazine. The magazine cooperates with a composite transfer device which penetrates into the sections during each interval of dwell of the conveyor to transfer from each section a freshly accumulated layer into the receptacle which happens to be in register with the respective section. The conveyor transports the cigarettes sideways, i.e., at right angles to the axes of the cigarettes. Reference may be had to commonly owned U.S. Pat. No. 4,362,235 granted Dec. 7, 1982 to Erdmann, and to commonly owned pending U.S. patent application Ser. No. 421,561 filed Sept. 22, 1982 by Erdmann et al.
The just described mode of accumulating arrays of cigarettes (e.g., customary arrays or blocks of twenty cigarettes each wherein two outer layers contain seven cigarettes each and the median layer contains six cigarettes which are staggered with reference to the cigarettes of the outer layers) is preferred over the earlier modes of gathering such arrays, namely, of accumulating a complete multi-layer block of cigarettes in a single section of the magazine and of thereupon expelling the complete block into the adjacent receptacle of an intermittently driven conveyor. Reference may be had to commonly owned U.S. Pat. No. 4,061,234 granted Dec. 6, 1977 to Bantien et al. The accumulation of a complete multi-layer array in a single section of the magazine takes up much more time than the accumulation of a single layer. In fact, the frequency at which complete multi-layer arrays are accumulated from discrete layers is a multiple of the frequency of gathering multi-layer arrays at a single location.
However, stepwise accumulation of multi-layer arrays by stacking successive layers on top of one another at each of several successive outlets of a magazine in a cigarette packing machine or the like also presents certain serious problems, particularly as regards the retention of cigarettes in incomplete arrays in optimum positions with reference to each other and with reference to the respective receptacles. In order to accumulate a large number of arrays per unit of time, the conveyor which transports the receptacles from section to section of the magazine must be rapidly accelerated and rapidly decelerated at a very high frequency whereby the cigarettes which form part of incomplete arrays in the receptacles are likely to change their orientation (particularly to lie askew) and to prevent the introduction of additional layers and/or undergo deformation of such nature that the resulting arrays must be discarded with attendant losses in output of the packing machine and expenditures for recovery of tobacco shreds from damaged cigarettes.
In accordance with an earlier proposal which is disclosed in the aforementioned commonly owned copending U.S. patent application Ser. No. 421,561 filed Sep. 22, 1982 by Erdmann et al., cigarettes in partly filled receptacles of the intermittently advancing conveyor are held against undesirable movements in response to abrupt acceleration or deceleration of the conveyor by stationary retaining or holding members which are adjacent to the path of movement of the receptacles. The receptacles are dimensioned in such a way that portions of the cigarettes therein are exposed and can be engaged and held by the stationary retaining members. Such retaining members can satisfactorily guide the cigarettes during travel in the spaces between successive outlets of the magazine but are incapable of preventing misalignment of cigarettes in partially filled receptacles during the last stage of deceleration of the conveyor and/or during the initial stage of acceleration of such conveyor, namely, when a partly filled receptacle is about to come to a full halt or is in the process of being accelerated for rapid advancement to the next outlet of the magazine unless the conveyor moves between the retaining members and the magazine. Thus, stationary retaining members cannot be installed in regions which are immediately adjacent to the aforementioned sections or units of the magazine because they would interfere with introduction of fresh layers of cigarettes into partially filled receptacles of the conveyor.
In accordance with another earlier proposal which is disclosed in the commonly owned copending U.S. patent application Ser. No. 470,569 filed Feb. 28, 1983 by Hoffmann et al., the apparatus employs a conveyor with receptacles whose volume or capacity is variable so that the capacity of a receptacle approaching the first section of the magazine barely suffices to receive a single layer, that the capacity of such receptacle is increased to accommodate a second layer when the receptacle comes to a halt in register with the next-following section of the magazine, and so forth. Such apparatus can reliably prevent misalignment of cigarettes forming part of incomplete arrays because the capacity of each receptacle is increased only when the conveyor is at a standstill and only to the extent which is needed to admit a single layer of cigarettes. However, the apparatus must employ a conveyor with receptacles each and every one of which must be adjustable to change its capacity, and the apparatus must also employ means for varying the capacities of successive receptacles at successive outlets of the multiple-outlet magazine. This contributes to complexity, sensitivity, initial cost and maintenance cost of the apparatus.